This invention relates to communications systems and particularly to an improved system in which the detectability of the radiated signals by means other than prescribed by the invention is materially reduced, and in which the vulnerability of the system to interfering signals, particularly intentional jamming signals, is substantially reduced.
It will be appreciated that two of the most important factors in a communication system are reliability and privacy of communication. This is particularly so in military communications, either for point to point communication, or in radar applications. It is an absolute essential requirement where the guidance of missiles is concerned. If the privacy of the system is invaded by breaking the code of the system, misleading signals can be radiated to deflect a missile from its target. If reliability is destroyed because of jamming, communications will be interrupted and in this manner a missile prevented from reaching its target.